Tire pressure control device



w. E. KAMM Erm. 2,976,906

TIRE PRESSURE CONTROL DEVICE Original Filed Sept. l0, 1958 March 28, 1961 5 Sheets-Sheet 1 INVENTORS Vlmbal 1. E, Kamm BY V'Lug Kraudcr' Kuri Saiger m-MM/Qgmmfam March 28, 1961 w. E. KAMM E TAL 2,976,906

TIRE PRESSURE CONTROL DEVICE Original Filed Sept. 10, 1958 5 Sheets-Sheet 2 Q Q N Q Q Q \9 Q JQ :B

ll' N "Q\ D W N N INV EN TORS Wunbaki I. E. Kamm BY Willy Kraulr- Kuri Sd-Ser March 28, 1961 w. l. E. KAMM ETAL 2,976,906

TIRE PRESSURE CONTROL DEVICE Original Filed Sept. 10, 1958 5 Sheets-Sheet 5 Y* Q E Q N INVENTORS QQ Wunibald LE. Kamm NQ BY muy Krauder Kuri Singer* 1.5. wpM/QJ @my Vlg March 28, 1961 W E KAMM ETAL 2,976,906

TIRE PRESSURE CONTROL DEVICE Original Filed Sept. 10, A1958 5 Sheets-Sheet 4 INV EN TORS Wunball E. Kamm BY Willy Krauer Kuri Sager Q. 5MM] @MMM H2M-4m March 28, 1961 W, l, E KAMM ETAL 2,976,906

TIRE PRESSURE CONTROL DEVICE Original Filed Sept. 10, 1958 5 Sheets-Sheet 5 /76 INVENToRs Wun'xbalcl I. E. Kamm BY Willy Krauer Kuri .Sagcr United States Patent O lice TIRE PRESSURE-CONT ROL DEVICE Wunibald I. E. Kamm, Stuttgart, Germany, Kurt Staiger, Indianapolis, Ind., and Willy F. Krautter, Portland, Pa., assiguors to the United States of America as represented by the Secretary of the Army Original application Sept. I0, 1958, Ser. No. 760,277,

now Patent No. 2,944,579, -dated July 12, 1960. Divided and this application Nov. 3, 1959, VSer. No. 856,884

5 Claims. (Cl. 152-417) (Granted under Title v35, U.S. Code (19152), sec. 266) The invention relates to improvements in tire pressure controls, particularly tire pressure controls of the centrallyregulated type whereby the tires of a vehicle may be inflated or deflated during operation of the vehicle.

This application is a division of our original application Serial No. 760,277 filed September 10, 1958, unowissued as U.S. Patent No. 2,944,579 dated 'July 12, 1960, for -Tire Pressure ControlDevice.

Itis well known that the -traction of vehicles on soft terrain may be greatly improvedbydecreasing the pressure within the tires thereby increasing the tire supporting surface, `and also that-a decreased tire pressure will provide fgreater ridllgeomforton rough roads. Conversely,

highftire pressures decrease Trolling resistance `and tire carcass temperatures on smooth roads therebyincreasing economy Vand safety. Therefore, means have; been proposed ,forchanging thetirepressure in vaccordance with thetype of surface .uponvwhich the vehicle is travelling, and many yof these means are of the type which permit the tire .pressure to.be-regulated whilefthe vehicle is inmotion. Y .One-1 of these arrangementsprovides for connecting the tire tube directly to a controllable compressed air source withinthevehicle. by means of conduits and .sealing structurebetween kthe axles Yandhubs.y The .primary disadvantage of this systemlies ;in the fact that-holding the tire pressure depends on the eflciency of the sealing structure, and, asthe seals aresubject to wear, it is verydifcult to maintain an effective seal at all times. Y Also, there is. the danger of ythe tires collapsing if -the sealing .system or compressedairfsourceshould completely fail. t 4.Another tire pressure` control arrangementprovides for asystemof double conduits and double sealingboxes on each Ywheel connected to a special tirer valve whereby.

compressed air within one conduit opens kor `closes the valve-while the-air .flowing through the other conduit `inflatesfondeates the tire. rAlthough this ksystem prevents the `airwithin thetires from-escaping due `to leaksin the sealingy boxes, the use of double conduits, double sealing boxes'and Adouble controls make the system complicated and'expensive. f

A more practical arrangement, which eliminates the disadvantages `of the above systems, uses a 'single conduit forboth-opening and closing the tire valve and inflating or deflatingthe tire tube by leaving the tire tube check valve within theyalve stem rendering the tire -pressure Vindependent-of leaks anywhere inthe system. This system employs-:adiferential piston or diaphragm placed onV the tirestem in operative engagement with the tubecheck valve. `The sides of the differential piston are in iluid connectionsuch that air pressure appliedk to one side of the 'piston -willalso be applied to the other side vof the piston,

however, the difference in piston areawill cause the piston to, m,ove, thereby opening the check valve. The .tire may befinflated by using a higherair pressure within the feeding line than is present inthe tire tube, and to deate the l 2,976,906 Patented Marf28, :1961,v

tireit is necessary to charge thefeedingline with apressure less than the tire pressure.` lfvall pressure-is .with-Y drawn fromthe feeding line, the spring in the check valve will seal the air within the tire. The primary disadvantages of this system are due to the check valve in the tire stem limiting the air flow, especially during deflation when there is little pressure difference between the piston and the tire tube, causing defiation to be too slow for many purposes. Also, the low pressure characteristicsvof this type of systemare largely'dependent on the strengthV of the check valve spring of each tire tube thereby producing uneven minimum tire pressures if the springs of the tires are not matched, as the-check valve spring lwill close the check valve when the pressure exerted by the differential piston is less than that exerted by the spring.

The invention pertains to improvements 'in the last mentioned type tire pressure control system whereby Vimproved operational characteristics are produced.

An object ofthe invention is to produce a tire pressure control system wherein inflation and deflation of the tire is rapidly achieved.

A further objectof the `invention is to Vdesign a tire operating valve wherein the opening mechanism and check valve comprise a single unit. l Y

Another object of the invention is toproduce a combined opening and check valve which is` economical to manufacture and may be mounted on any tire stem without modification to the stem.

Yet another object of the invention is to produce a combined opening and check valve structure wherein the spring and area of the valve kare of such valves as to con-` Fig.V 2 is a cross-section elevation of a modification ofi combination. valve.

'.Fig. 3 is acrossisection of a-type of sealing means used with non-driving Vwheels. employing thetire control system.l

Figs. 4, 5 .and6 ldisclose. Vvarious types of sealingmeans` used with driving wheels employing the tire-,control system offthe'invention. f 'f .-Fig. v.7 is a .schematic view lof the control lever-andy valves in theuinflating position.

Fig. 8 -is Va schematicsview ofthe :control lever and' lvalves in the pressure reading position.

Fig. 9 vis .a .schematic view of the control lever and valves in the deflating position.

Fig. 10 is a schematic view of the control lever and valves in the exhausting position.

The invention may be used with any `typeofpneumatif: tired vehicle, and in the -illustrated'embodiment a form of opening and eheckcombination valve is shown at 10, which is of the type utilized with the invention. yValve 10 consists of a housing comprised of an upper portion 12 formed to a lower portion 14. Portion `12 is provided with anextendingnipple 16 onto which a feed or pressure line may be connected,-the-va1ve 10 may be threaded to the .top of a tire tube valve stem 15 .by means of threaded orifice 18. Before the valve 10fis attached to the valve stem, the valve stem check valve must be removed whereupon the orifice 18 is screwed upon the valve stenruntil the stem engages sealing ring `20m-form an airtight connection.

A differential piston 22 is-,supported within combina-,

tion valve 10 and consists of a large diaphragm 24 and by a tubular rivet type fastener 28 acting on washers 30 and 32. A spacer 34 maintains the diaphragms 24 and 26 in spaced relation while the bore 36 will permit equal airpressure on bothisides of piston 22. The periphery of the diaphragms 24 and 26 are spaced by a sheet metal spacer 38 and held in place by housing portions 12 and 14, which are assembled by folding under lip 40. A vent 42 opens into the space 44 to prevent inconsistent performance due to air leakinginto space 44 and building up a pressure.

A valve seat support 46 is also held in place by the assembling of housing portions 12'and 14 and is formed with a valve seat 48, which is part of the check valve structure. A guide bracket 50 is mounted within housing portion 14 and serves to guide stem 52 which carries spring 54 biasing check valve 56 in engagement with valve seat 48. A contact 58 extends from the upper end of stem 52 for engagement with piston 22 and is formed with ai; passages therein. The area of the air passages in fastener 28, contact 58, support 46, bracket 50 and ring are all greater than the area of the air passage of thetire tube valve stem 1S, therefore, the rate of flow of air is limited by the tube stem rather than the combination valve 10. i

The operation of combination valve 10 is as follows:

After the valve stem check valve has been removed, valve 10 is threaded onto the valve stern 15, and a source of compressed air is attached to nipple 16. To inate the tire an air pressure greater than that of the pressure within the tire is introduced into valve`10. vThe air will` flow to both sides of piston 22, and, since the area of diaphragm 24 is greater than that of diaphragm 26, the piston 22 will move downwardly toward contact 58. As contact 58 is displaced, the check valve 56 will be opened permitting the air to flow into the tire. When the desired tire pressure is obtained, the pressure of the ai1 being introduced into valve 10 from the compressed air source is reduced to atmospheric pressure by exhaust to the atmosphere as hereinafter described so as to return the pressurervvithin valve 10 to atmospheric, thereupon Vthe spring 54 will close check valve 56 and the pressure within the tire acting upon the area 60 of check valve 56 will keep check valve 56 seated. A

When it is desired to deflate the tire, air is introduced into valve 10 through nipple 16 at a pressure lessthan that of the tire but greater than ,atmospheric `pressure whereby the large pressure area of diaphragm 24 will cause ,check valve 56 to be opened,l since the pressure within valve 104`is less than that ofthe tire, the air will ow to thelowerpressure differential deating the,tire.

The spring 54` and area 60 are, constructed vsuch that when the air within the tire reaches the minimum safe operating pressure the check valve 56'will-be closed and held shut even through Vthere is pressurized air withinv valve 10. This is due to the pressure exerted ,by spring 54 and that of the air within the tireon area 60 being greater than the differential pressure exerted. on piston 22 by the air from the compressed air source.V .Thisrconstruction is especially important where oneof the tires. of the vehicle is leaking. Under these conditions the reduced pressure within the leaking tire reduces the force required to open the check valve S6 permitting air to be introduced into the leaking tire Without'disturbing the pressure of the remaining tires. This would permit the leaking tire to share part of the vehicle load and preventl overloading the other tires until repairs can be made.

of a single piece of material; contact 58' is carried by piston 22' and upon piston deection is adapted to engage check valve 56. Check valve 56 is biased and guided in the same manner as the check valve 56 of Fig. 1. Valve seal 62 contacts valve seat 48' which consists of an annu- #lar lip depending from support 46'. The construction of the check valve 56 and valve seat 48 of this modification minimize any tendency of the valve to stick and profriction bearings 68. The air is conducted through the axle, via conduits 70, which are connected to the compressed air source and terminate in orifice 72 which opens onto the surface of axle 66.

An annular recess 74 Within hub 64 contains the sealing means 75 which is comprised of concentric tubular sleeves 76 and 78 held in spaced relation by spacers 80. Tube 82 provides an air passage through sleeves 76 and 78; rubber lip rings 84,'which are mounted to sleeve 78, provide the immediate seal between the hub 64 and axle 66. Lip rings 84 are inclined toward orifice 72 such that:` the air pressure will cause rings 84 to be pressed against axle 66 and maintain a tight sealing action. Resilient sealing rings 86 are held in place by retaining clip 88 and enclose recess 74 and ring 76 thereby creating an airtight chamber 90 except for passageways 82 and 91 which allow the compressed air to pass through chamber 90 on its way to coupling 92. Y

The air is conducted from chamber 90 to coupling 92,-

via conduits.94, whereupon the air will be transferred to the wheel 9'6and to the combination valve 10 through conduit 98. Coupling 92 may consist of a rubber sleeve into which a nipple 102, supported by wheel 96, may` be fitted. Thus, the valve 10 will be in communication' with a compressed air source when the Wheel 96 is bolted to hub 64. Y y Fig. 4 discloses one type of sealing structure which may be used with a driving wheel, wherein a hub 104 rotates aboutraxle housing 106. A iitting'108 permits an air hose to be attached thereto such that air may ow through conduit to seal 112. Seal 112 is composed of tubular rings 114 and,116 which surround axle 118 and support a lip ring 120. Passages 122 permit a iow of air' through the rings 114 and. 116 to the void between axle 118 and housing 106. Sealing rings 124 position seal` 112 and together withlip ring 120 prevent air from escap-l ing to the diierential.` The end of housing 106 is sealed by, an annular krubber gasket 126 which has a lip 128 formed thereon which will be pressed against the housing' wall by air pressure within housing 106. A hole 130 is bored in housing 106 to permit'communication from the void between axle 118 and housing 106 and sealing means 75, which is of the type disclosed in Fig. 3. From seal 7S the air will travel through conduit 132 to the wheel as shown in Fig. 3.

A modification of sealing means for a drive Wheel is shown in Fig. 5 where the axle housing 106 rotatably supports wheel hub 104. Air is introduced into seal 11,2 inV erating nut 142 which is rotatably mounted on support Y 144. The air is thus prevented from leaking through the bearings and is fed, via conduits 146, to coupling 92.

Another seal modification is disclosed fora driving` wheel in Fig. 6. The air is fed through the axle housing 106 by means of fitting 4108jand conduits 11'10 andis preventedLfrom escaping'to the di'lerential by annular sealing ring 1148. Seal ring 148 is made of aresilientfmaten'al and is formed with a lip 150 and shoulder 152-such that the seal 148 is held in place-by the engagement of housing shoulder 154 with shoulder 152, and the air pressure surrounding axle 118 will cause lip 150 to cling to axle 118 vforming an airtight seal. The resilient character of ring 148 will bias the lip 150 away from the axle 118 when the system is not'under pressure thereby keeping wear to a minimum. Bearing 156 is rendered airtight by means of aseal 1'58. Seal 158 is also of the liprtype and is mounted adjacent oil seal 160 -by a sheet metal cover 162- Conduits 146 carry the vair through hub 104 to coupling 92 as in Fig. 5.

Figs. 7 through 10 illustrate the control valvesfor-regulating the flow of air vin various positions ofoperation and will be explained in operational sequence.

Fig. 7 discloses the inflation operation wherein conduit 164 supplies air from the compressed air source to a variable Y'liow intake valve 166 controllable by stem 168i. Conduits '170 and 172 connect valve 166 to variable ow exhaust valve 174, which is operated by stem 176, whereby air maybe exhausted to the atmosphere, via conduit 178. A pressure gage 180 is included `in the system 'and is aliixed to conduit l172while conduit 170 provides the connection to the combination tire valves 10, one of which is shown. A manually operable pivotally mounted lever 182 may be used to actuate stems 168 and 176.

When the handle 182 is raised, as in Fig. 7, stern 168 will be depressed pressurizing the system, causing the differential piston 22 of the combination valves 10 to open the check Valve 56, permitting air to flow into the tires, inflating them.

During ination it is necessary to check the pressure within the tires to prevent over-ination. Gaging is accomplished by moving handle 182 to the position shown in Fig. 8. In such case both valves 166 and 174 are closed and the static pressure within conduits 170 and 172 will be that equal to the pressure of the tires as the pressure within conduit 17,9 and valve will hold the check valves 56 open. The pressure within the tires may now be read from gage 180.

Should the pressure within the tires be higher than that desired, the tires may be deflated by moving handle 182 to the position illustrated in Fig. 9. During the deation operation exhaust valve 174 is only partially opened whereby air pressure within conduit 170 and valve 10 is slowly relieved. As explained previously, a reduced pressure in valve 10 will hold check valve 56 open as long as the dilerence in force exerted on diaphragms 24 and 26 is greater than the force exerted by spring 54, therefore, the air pressure within conduit 170 and 172 may be less than the pressure of the tires and yet hold the Valve 56 open. Because of the greater tire pressure, the air will flow from the tire through valve 174 and be exhausted into the air until valve y174 is closed or the pressure within conduit 170 and valve 10 reaches the point where the diierential pressure acting on piston 22 can no longer counteract the force of spring 54 at which time the check valve 56 will close and the tire will be sealed. As the conduits 170 and 172 are usually completely void of pressurized air except when the tire pressure control system is in operation, it is necessary to raise handle 182 to the inating position to pressurize the system and open valves 56 before the deflation operation can be performed.

When the proper air pressure has been achieved in the tires, the handle 182 is moved to the position shown in Fig. 10. In this position the stem 176 of exhaust valve 174 will be fully depressed allowing any pressurized air within conduits 170, 172 or valve 10 to be exhausted to the atmosphere. The lack of air pressure within combination valve 10, as the system is exhausted, will permit check *valve c'56to close under the inuence of spring S4' thereby holding the tire pressure.

The vehicle will normally be operated while rthe system is e'xhaustedthereby permitting the sealing lips of seal rings 84, 1134 and 148 to retract from engagement with the axle or axle housing, due to the resilient nature of the ring, vthereby preventing unnecessary wear of the sealing means.

It istherefore seenthat the invention discloses a simplilied tire pressure control system wherein the tires may be inflated or deflated from a `single conduit and that the tireis sealed from the control system except during operation of the-system, thus leaks in the conduitsfor seals will not afr'ectthe tire pressure.

The integration of `the check valve with the opening and closing-piston structure achieves accurate and consistent performance vat each tire as the area of the check valve Yandstrength `of the closing spring may be accurately maintained and will not vary with each tire. Also, the dimensions ofgthe` combination valve air passages are greater than the core of' tire valvestem thereby permitting theymaximumfpossible ow of air into or out of the tire.

' Theuse of lip type seals has special advantage with thedisclosed `system as thelips may be constructed so as to engage -the=`-moving element only when compressed air -is xintroducedinto lthe seal, therefore, as vthe control' system of the invention is pressurized only when the tires are being inflated or dellated, the seals will be subject to wear for a minimum length of time.

1t is understood that various modica-tions may be apparent to those skilled in the art without departing from the spirit and scope of the invention, and the invention is not to be limited to the illustrated embodiments except as included in the appending claims.

We claim:

1. In a tire pressure control system for a vehicle mounting an axle and a wheel hub rotatable thereon; a conduit formed in said axle terminating in an orice formed in the surface thereof, sealing structure contained Within a recess of said wheel hub, said sealing structure including a set of annular sealing rings encompassing said axle and axially positioned on both sides of said orifice, lips formed on said sealing rings projecting toward said orice, holding rings positioning said sealing structure within said recess, a coupling within the wheel supporting flange of said hub anda conduit connecting said coupling with said recess whereby compressed gas may ow through said axle to said coupling.

2. In a tire pressure control system for a vehicle mounting an axle and a wheel hub rotatable thereon; a conduit formed in said axle terminating in an orifice formed in the surface thereof, sealing structure contained within a recess of said wheel hub, said sealing structure including a pair of spaced concentric outer and inner sleeves encircling said axle, a passage through said sleeves, a series of sealing rings carried by the inner sleeve encircling the axle and axially positioned on both sides of said orifice, resilient lips formed on said sealing rings projecting towardsaid orifice, holding rings interposed between said outer sleeve and said recess, a coupling within the wheel supporting flange of said hub and a conduit connecting said coupling with said recess whereby compressed gas may flow through said axle to said coupling.

3. In a tire pressure control system for a vehicle mounting an axle, an axle housing and a wheel hub rotatable upon said housing; a conduit extending through the axle housing, a rst seal interposed between the axle housing and the axle, said seal being formed with a resilient lip in close proximity to the axle, a second seal interposed between said axle and the end of said axle housing, a hole in said axle housing, a third seal carried within a recess in said wheel hub adapted to engage said axle housing and enclose the area adjacent said hole, a coupling within the wheel mounting ange of said hub and conduits means within said hub connecting said coupling 7 with said recess whereby pressurized gas maybe conducted from said axle housing to said coupling.Y

4. In a tire pressure control system for a vehicle mounting an axle, an axle housing, and a wheel hub rotatably mounted upon said axle housing by means of oil sealed bearings; a conduit within said axle housing, an annular resilient seal interposed between said axle and axle housing, an elongated lip formed on said seal and extending parallel to said axle in close proximity thereto, a shoulder formed on said seal adapted to engage a shoulder formed on said axle housing, a second resilient seal lixed to the oil seal of said bearings, a lip formed on said second seal, a coupling within the wheel mounting ange of said hub and a conduit connecting said coupling with the inside of said hub whereby compressed gas may be conducted through said axle housing to said coupling.

5. In a tire pressure control system for a vehicle having a non-driving wheel hub rotatably mounted on a first axle and a driving wheel hub rotatably mounted on a spaced housing of a second axle, a first conduit formed in said first axle terminating in an orice formed inthe surface thereof, sealing structure lcontained within a recess of said non-driving wheel hub, said sealing structure including a set of annular sealing rings encompassing said rst axle and axially positioned on both sides of said orice lips formed on said sealing rings projecting toward said oriice, holdingrings positioning said sealing struc` ture within said recess, a coupling within a wheel supporting ange of said non-driving wheel hub, a second conduit connecting said coupling with said recess, a third conduit extendingthrough'said housing of said second axle, a first seal interposed between said housing and said second axle, said first seal .being formed with a resilient lip in close proximity to said second axle, a second seal interposed between said second axle and the end of said housing, a hole in said housing, a third seal carried within a recess in said driving wheel hub adapted to engage said housing and enclose an area adjacent said hole, Va second coupling within a wheel supporting ange of said driving wheel hub, and conduit means within said driving wheel hub connecting said second coupling with the last mentioned said recess, whereby pressurized gas may be conducted through said rst axle and said housing of said second axle to the respective ones of said first and second couplings.

References Cited in the tile of this patent UNITED STATES PATENTS 1,040,643 Darnley Oct. 8, 1912 1,657,023 Mitchell et al. Jan. 24, 1928 1,800,780 Daneel Apt. 31, 1931 

